Aliexpress
Click here… to search for MINI ES-A7 4mm Bit Set on Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (9.20 USD): BGAFF10OFF
Coupon (9.20 USD): bGhOnEy10
(CouponsFromChina.com tip: you should apply the coupon in your cart after clicking “Proceed to checkout”. Click to copy code and open shop)
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): 502C6B, 20tools, e2bcea, AFfbG10, BG2020NS, BGVDay10%off, BGMPB2020
(probably won’t work, but you can try them out)
Price history and price alert
Price history (for all/most countries) for MINI ES-A7 4mm Bit Set is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).